Method for making covered elastic strands



Aug. 27, 1929.

l. B. 'cHlsHoLM IETHOD FOR IIAKING COVERED ELASTIC STRMJDS nud July 1, 1927 v 4 Sheets-Sheet 1 Aug. 27, 1929. L B. CHISHOLM 1,726,099

METHOD FO MAKING COVERED ELASTIC STRANDS Filed July 1, 1927 4 sheets-sheet 2 a@ na ATT mRpI-LJB:

Aug. 27, 1929., L. B. cHlsHoLM METHOD FOR MAKING COVERED ELASTIC STRANDS Filed July 1. 1927 4 Sheets-Sheet .3 y

foil @Mir/'1% w FEE- Aug- 27, 192,9. L B. cHlsHoLM 1,726,099

METHOD Fon MAKING COVERED ELASTIC STRANDs Filed July 1, 1927 4 SheetsjSheet 4 AT TURN E115:

Patented Aug. 27, 1929.

UNITED STATES 1,726,099 PATENT oFFIcE.

' LESTER B. CHISHOLM, 0F STONEHAM, MASSACHUSETTS, ASSIGNOR T0 135711113113ASTIIK,` NC., OF CHELSEA., MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

METHOD FOR MAKING COVERED ELASTIC AS'JJIB'AN'IDS.

.Application led July 1, 1927. Serial No. 202,906.

The invent-ion relates to a method for making covered elastic strands which comprise a covered elastic core and a fibrous thread covering wrapped around the core and in 5 which the core is cemented to its covering Cil to prevent slippage and creeping of the core within the covering in case the core is sev-y ered, the core lying normally within its covering under tension.

Owing to the useof a liquid cementing` material or rubber cement in the making of these covered strands for cementing the core to it fibrous covering, difficulties have been experienced in the making of the strand among which are noted the following: Such application of the cementing material as will effect a proper bond between the core and its covering as will prevent creeping of the core especially when the core is highly tensioned, and at the same time will not inter* fere with the normal elasticity of the core and pro er functionin of the covered strand in any abrio of whic it may form a part. A too free application of the .cementing material is apt to make a too sticky and gummy thread which is not only unsightly, but is apt to bond together the coils of the fibrous covering -Which interferes by acting as a drag upon the elastic core. `The application of the thread covering and the cementing material should be such as will effect a proper bond between the elastic core and its covering, as noted above, but no more, the coils of the fibrous covering being free to ride upon the core as it is highly tensioned or allowed to relax.

Another difficulty arises on account of the nature of the cementing material employed consisting as it does of a rubber cement 0r other elastic cement.A These cements are of a very sticky or gummy nature. They dry quickly when exposed to air and will accumulate or mass on exposed surfaces. In consequence hardened pieces or bits of the cement are apt to be picked up and fasten themselves to the strand during the cementing operation and these pieces are apparent and disfigure any fabric in which the elastic strands are used.

The general object of the invention is to overcome the difficulties above referred to, and I have found they may be overcome by practising the coating operation according to the following method: e

The elastic core to be covered is tensioned to an extent greater than its normal tension, or,-in other words, the tension under which the core 'lies in the normal unstretched strand, it being understood that in an elastic strandthe core lies within the strand under some tension. The amount of tension given the core is preferably an amount determined by stretching theelastic strand to an extent just short of its normal stretch. To the elastic strand thus tensioned athread covering is applied in the usual manner. This thread covering may consist of a single thread or a number of combined threads. The thread covering is soapplied that a space will separate its coils. The amount of space between the coils is commensurate with the amount of stretch desired to be attained in the 'completed strand. That is, as the core is allowed to contract the coils will be brought together limiting further contraction of the core which will then be held tensioned within the covering and accordingly the amount of separation of the coils determines the amount of stretch desired to 'be obtained in the completed strand. I

separated from one another, is passedthrough a bath of cementing material in order that the cementing material may enter between the coils of the thread covering and form a bond between the thread covering and the elast-ic core, cementing the one to the other. yWhen applied in this way I have.

found that the ordinary rubber cements are inadequate inasmuch as they will not properly enter between the coils of the thread covering and form such bond between the core and its covering as will properly cement the core to the covering. I have found, however, that if a water-dispersed rubber or water emulsion of rubber be em- After passing throughthe bath of cementing material the covered strand is then freed of surplus cement before the strand has been exposed to the air. In connection with this freeing of the strand of surplus cement, it

is desirable that the covered strand be freed in so far as possible of all cementing material other than that remaining to form a proper bond between the core and its covering.

After its freezing of surplus cementing material, the covered strand with core still tensioned has applied to it an outer thread covering, care being taken that before the application of this outer covering the initially covered strand shall not contact with any surface on which cementing material might accumulate and harden, or, in other words, any surface from which bits or pieces of the cementing material might be picked ofi' and adhere to the running strand. The outer thread covering is applied in the same manner, with substantially the Same spacing of coils as the inner covering, except that the spirals are preferably made to run in a\reverse direction. This outer covering is for the purpose of adding finish to the thread and by enveloping the inner covering, bearing more or less cementing material on its outer surface, prevents it from gumming mechanism or rolls over which the strand isl led and to which, were it not for the outer enveloping covering, cementing material from the inner covering might adhere and accumulate and be picked off in small bits or pieces from time to time by the running strand, it being a very diicult matter to eliminate all surplus cementing material from theouter or exposed surface of the initial covering after running through the bath of cementing material.

After the application of the outer enveloping covering the strand is passed on, allowed to relax and afterward wound in the usual manner.

Instead of first applying a thread covering t0 the elastic core before running through the bath of cementing material, the core is first run through this bath before winding with the thread covering. In such case instead'of using a bath of water-dispersed rubber or water emulsion of rubber as before, an ordinary thin rubber cement may be employed provided the rubber solvent in the rubber cement is not such as will injure the elastic core. After passing through the bath of cementing material the elastic core is freed of surplus cement before the core has been exposed to the air the same as before and afterward a thread covering is applied to the elastic core which then bears a thin film of cementing material, care being taken that before the application of the thread covering the coated core shall not contact with any surface von which the cementing matei'ial might accumulate and harden and bits thereof afterward picked off by the running core. The thread covering thus applied is applied with coils separated from one another according to the manneru of application of the initial thread covering in the ing is not necessary. It may be applied, f

however, if desired to give further finish to the strand.

The method and variations thereof can be better understood in the light of the apparatus shown in the drawings for practising it, and in which- Figure l isa side elevation of the machine.

Fig. 2 is a front elevation thereof.

Fig. 3 is a vertical section of a portion of the machine.

Fig. 4f is a vertical section of the cementholding receptacle and mechanism incidental to it.

Fig. 5 is a plan of the cement-holding mechanism as shown in Fig. 4.

Fig. 6 is a cross section of a detail of construction of the cement-holding mechanism shown in Fig. 4.

Fig. 7 is a vertical section showing a modiied and preferred form of the cement-holding receptacle and mechanism incidental to it.

Fig. 8 is a section on the line-"8-8 of Fig.

Fig. 9 is a section on the line 9-9 of Fig. 7.

Fig. 10 is a plan of the cement-holding rece tacle shown in Fig. 7.

Flg. l1 is a planof one of the completed elastic strands having a single covering, and

Fig. 12 is a plan of one of the completed elastic strands having a double covering.

Referring to the drawings 1 represents the frame of the machine. Secured to this frame are brackets 2 on which are mounted rotary 4thread-bearing spools 3 and 4 respectively. rlhese spools are arranged in vertical alignment one above and spaced from the other, the spool 4 being arranged above the spool 3.

Each spool is mounted upon its bracket by a connecting base piece 5 fixed to the bracket and on which turns a spindle 6 driven by a whorl 7. The spool fits upon the spindle and is driven by the whorl to turn with the spindle by a pin connection 8 between the spool and the whorl. Loosely arranged on the end of each spindle is'a collar 9 carrying a flyer 10 and held in place by a nut 1l which nut is fixed to the spindle. This spool mechanism with attending flyer is of a type commonly employed in the winding of covered elastic cores, the fiyer being operated by the thread as it unwinds from the spool.

In connection with the'arrangement of the spools and their operating mechanism it will be observed that the spool 4 and its attending mechanism are arranged in an inverted position with relation to the spool 3. In

other words, the spool 3 and mechanism associated with it lie above its supporting bracket; while the spool 4 and its associate mechanism lie below its supporting bracket 5 de nding therefrom. 1

. f51e spools are both turned by an endless belt 13 passed around their respective whorls 1n a manner to rotate the-spools in reverse directions. To this end the belt passesaround a driven pulley 14; thence extends downward around' an idler pulley 15; thence around lthe whorl of the -s ool 3; thence re? turning passes round-an i ler pulley 16 and upwardly around an idler pulley 17 and thence 'around the whorl of the spool 4 and back` to the'pulley 14 and point ofb beginning. The various idler pulleys are mounted on the frame of the machine. The driven ulley 14 is' mounted 20 upon a shaft 18 whlch turns withm sult` able bearings on the frame. The shaft 18 is driven from 'a driven shaft 19 by means of a belt 2,0 which runs around pulleys 21 and 22, respectively, fixed to the respective 25 shafts. The shaft 19 is suitable source of power.

25 is the thread carried by the spool' 3 and 26 is the thread carried by the spool 4.

27 is the elastic core.- This core consist- 36. ing usually of a common elastic thread 1s arranged upon a spool 28suitably mounted on the frame. From this spool the core extends around a pulley 29 and thence upwardly through the spindles of both spools where 1t continues over an idler pulley 30 and a series of pulleys 31, 32 and 33 respectively forming part of a takeup mechanlsm commonly employed in similar connectlon's'. The a'rrangement is such that. the elastic core will 4o be tcnsioned in its passage by and between 'the spindles of the respective spools and to this end the spool 28 on which the core is wound may be provided with any suitable tension device (not shown) by which tension may be imparted to the core as it is drawn olli' its-spool bythe take-up mechanism.

Located in the space between the spools is a receptacle 35 holding cementing ma terial 36 and through which cemcnting material the tensioned'elastic corev is directed to pass. The cement-holding receptacle is sup'- ported by means of a bracket 37 fixed to the frame. The core is directed to pass through the cementing material by passing it first over an idler pulley 38 fixed-'to the under side of the receptacle, thence over idler-pul leys 39 and 40 respectively fixed to the side of the receptacle and by which the core is directed to pass over the top side edge of the receptacle downward into the cementing material within it. There the elastic core passes over an idler pulley 41 which is carried by a support 42 consisting of a bar secured to the bracket 37 and bent to eX- tend upwardover the side of the receptacle 44 which spans the chamber pf driven from any above the opening lingly the action and downward into the interior thereof for Supporting the Pulley 1l-@Aften Hessing alOlnd the pulley 4l. thegge Legiteggdsugpward through an opening ,4 ,ii1l a rqssbar receptacle and fixed totheopposite s ides ,there 0ftz-frliilml 'ml' olfml 'Fixed to the crossbar 44g isf a :sbrapen-f45 having through it a vpassa'gejml fthrofugh which the core is directediix,,fp'assqof'llhev 75 scraper' is preferably madeinlstwo.' halvlesftou avoid the necessityofV threa'dingnthearco're through it. .The two halvesvarei/chmbined in propercoordination to'fi-'n-.vtliespassage 46 bypins 47 and are securely il'heldtogethr 80 y means of a spring clip48'avhicli i'sasil tened to the crossbar 44 andiithefopposite jaws 49 of which embracerftlieI respective halves of the scraper, being'bent tosfitfwithin grooves 50 therein, therebyiholdingnthe 85 two halves of the scraper-'securelyfinvplace fon-forming the complete rscraperiand vlifiring it to the crossba-r 44. Tlislthe scraper-is built around the elastic core=1to avoidr. tlle necessity, as explained above,1f'o'f` threadingy 90 the elastic core :through itsu 1 The'b'o'dy olthe'`l=v spring clip 48 fixed to the1 crossb'ar1-44," lies 43 *inf` the 'cros'sbar through which the elastic"corefextends,'farid accordingly is itself provided with anlfop'en-t P5 ing 52 through which the corefpfasses'i -The""" passage 46 through the scraper'- is oneJ bly large enough to permit `of'''the-ff..passagefof the core through it'or passagejoffthec'ore having an initial thread"coveringifupon'fit 10 when such covering is employed; A'ccor'd-l of the scraper'fis 'tojremove from the core all surpluscementingnaterial. yThe scraper, it willfbe ob's'err'fe l,fis so arranged thatl the lower *'end'thereot throughr which the core rs't' passes will"- lie fa t" 5' all times within the cementing'flma'trial. Therefore as the surplus cementiisremoved from the coreit simply remains'-asnfpart t' the bath of cementing material andj'ther'e'l is 110 no opportunity for 'it to accumul'z'tfef'rharden in the scraper. The v'o`n'ly'f" otlierplar'ze where the cementing material'might-"accumulate or harden and sobepikedlol by the running core is at the top e'ndothe 115 scraper which lies above the bo'dyifl'crenting material and accordingly is erpofsedi tio the atmosphere. he top ,end of the'scraper is, however, provided with a sharpiedet' on which no cement can accumulate and. 2 harden so as to be picked olf by theifuiinin-g core. This'sharp edge is formed inclining or beveling the top en" "'fthe scraper. j "f f Thus it will be seen thatbefoi' r" finglx its outer thread covering" aftimpssinlg through the bath of cementingf'iiiteriahiiot only is all excess cementl'scape mthfe core, but care is exercisedtli' ated which the cementing material might accumulate and harden so as to be picked off and adhere to the running core. l In Figs. 7 to 10, inelusi\-'e,'there is shown a further and preferred example of a receps tacle. for holding cementing material'tln'ough which the elastic core is directed to pass to become coated with the material within the receptacle, and whichreceptaele has combined with it 4'means whereby excess coating; -may' -inclined orcam surfaces 62 ouits inner side or face. The end closures are also provided with int-urned jaws 63 which Aare adapted to extend over the anges ou the' respective ends ofthe receptacle Vto lie back of and have drawing engagement with the cam surfaces 62 onthe inner sides or faces thereof, entrance being permitted b v way of the. slot 6l. Thus connected the end pieces may be securely fastened to the ends of the receptacle forming tight jointed connection therewith, but permitting ot the removal ot' the end pieces as occasion may require.

Interposed between the bottom end piece 58 and the bottom end of the receptacle is a rubber washer 6i which assist-s in making a tight connection between the receptacle and its bottom end piece. The bottom end piece SS has an opening 65 in it which opening is extended through the rubber washer 64 and it is through the opening thus provided that the elastic core passes to pass upwardly through the eementiug material 66 contained within the chamber ot the receptacle. The rubber washer closes snugly around the elastic core at the oint where the core passes ihrough it forming at this point a tight joint preventing escapeof cemeuting material at the point where the elastic eoreis entering. At the top oj the receptacle the top end piece 59 is provided with a relatively large opening 67 around which the end piece is provided with an upturned llangc 68. Covex-ing this opening and bearing against the flange 68 is a rubber pad 69 which functions as a scraper as will presently' be explained. The pad 69 is held in place crushed against the flange 68 to form a tight joint therewith by means of a plate 70 provided with out-turned ears 71 which lock under cams 72 arranged on posts 73 upstanding from the top end of the top end piece 59. The rubber pad 69 has an opening 74 through it through which the elastic core is directed to: pass afterhaving passed through the cementing material and vwhiehopening is continued through the top plate 70. The opening through the'rubber 'pad is such as will permit the elastic core to pass through it, the pad, however, fitting snugly around the coated core and accordinglyA functioning as a scraper to remove from it all excess ce- ",menting material which when removed re- -yturns into the body of the cementing material contained `within'the receptacle. The receptacle forms substantially an airtight closure so thatall cementing material remov'ed from the core before the coated-core becomes exposed to the atmosphere and ac-' cordingly the removed cementing material will not accumulate and harden upon the scraper, but will remain in soft liquid eondition and return to the bat-h of cementing material.

The operationis as follows: Assuming the elastic core is running under suitable tension through the spindles of the respective spools and through the bath of cementing material lying between the' spools, the

tlu'ezul-Q'carried by the spool 3 is first wrapped around the running core, the winding being such, as previously explained, that coils o't the winding will be properly spaced from one another in order to permit of the relaxing of the core and also to permit of the cementing material entering between the coils ot the thread covering and cementing them to the core.l After the initial winding ot the. core by the thread 25 the covered core passes through the bath of cenlenting material after-which the excess cement is wiped olf by passing the covered core through the restricted opening or passage of the scraper and lbefore exposure to the atmosphere;

thence the covered core paises to receive the secondary or exterior covering provided by the thread 26 carried by the spool 4. No opportunity is given, as before explained,

for the running core to have contact with any surface to which cementing material from the coated core may adhere andaccumulate and harden to be picked oi by the running core. The thread 26 is wound in 'precisely the same manner as the thread 25 with proper spaces between the coils but preferably in a reverse direction to the winding ot the thread 25. that the winding of the thread 26 or outer covering is provided before the initially covered core is. allowed to pass through the spindle of the spool 4 and it is for this reason that this spool and its associated mechanism are arranged in an inverted position It will be observedso that its flyer may lay the thread before the initially covered core has opportunity to pass through the spindle of the spool olf which the thread is wound, as this would present a surface to which cementing mate- A ndary or outer covering is necessary.

1,7ae,oa9 Y rial from the coated core mi ht adhere to accumulate and harden and e picked olf by the running core. After the application of the outer covering the 'covered core passes through the spindle of the spool 4 and thence provided by the thread 26 oi the spool 4c.4

In such case the cementing material employed is preferably the water-dispersed rubber or water emulsion of rubber the same as before, but any thin rubber cement might be. employed provided its solvent would not injure the elastic core.

With those cores which are passed directly through the cementing material and aftery ward receive a single'thread'covering no sec- One : ma k\be added, however,.if desired to give linish`\j`ust'as it is sometimes added to ordinary` covered elastic strands.

Having thus fully described my invention, I claim and desire to' secure by Letters Pat-` ent of the United States l. The method of making elastic strands having an elastic core and a thread covering cemented to the core, which comprises running the core tensioned through a bath of cementing material capable of adhering to the core, removingexcess cementing material from the core and afterward winding a' thread coverin r on the coated core still tensioned and before it has contact with any surface to which the cementing material thereon may adhere and accumulate and harden and afterward be picked off by the running core.

2. The method of making elastic strands r having an elastic core and a thread covering cemented to the core, which comprises running the core tensioned through a bath of cementing material capable of adhering to the core, removing excess cementing material from the core before exposure of the core with applied cementing material to the atmosphere, and afterward winding a thread covering on the coated core still tensioned with coils of the covering spaced from one another. A

3. The method of making elastic strands having an elastic core and a thread covering cemented to the core, which comprises running the core tensioned through a bath of cementing material capable of adhering to the core, removing excess cementing mate- -.rial from the core before exposure of the core with applied cementing material to the atmosphere and afterward winding a thread `covering onV the coated core still tensioned with coils of the covering spaced from .one another after the exposure of the coated core to the atmosphere 'and before the coated core has contact with anysurface on which the cementing material may accumulate and harden to be vpicked'oif by the running core.

4. The method ofmaking elastic strands having an elastic core and a thread covering cemented to the core, which comprises running the core tensioned through a bath of cementing material capable of adhering to the core, removing excess cementing material vfrom the core to leave a relatively thin film of cementing material thereon before exposure of the core with applied cementing material to the atmosphere and afterward winding a thread covering on the coated core still tensioned with coils of the covering spaced from one another after the exposure of the coated' core to the atmosphere and before it has contact with any surface to which the film of cementing material thereon may adhere toaccumulate and harden and bepicked oft by the running core.

5. The method of making elastic strands having an elastic core and a thread covering cemented to 'the'core, which comprises running the core tensioned through a bath of cementing material capable of adhering tol the core and contained within a receptacle closed from the atmosphere, removing excess cementing material from the coated core before it has extended outside the chamber of the receptacle and afterward winding a thread covering on the coated' core still tensioned with coils of the covering spaced from one another.

6. The method of making elastic strands having an elastic core and a. thread covering cemented to the core, which comprises Arunning the core tensioned through a bath of cementing material capable of adhering to Ythe core and contained within a receptacle closed from the atmosphere, removing excess cementing material from the coated core before it has extended outside the chamber of the receptacle and afterward winding a thread covering on the coated core still tensioned with coils of the covering spaced from one another after the exposure of the coated core to theatmosphere and before it has contact with any surface on which the ceinenting material may accumulate and harden to be icked olf by the running core. 7. Themet od of making elastic strands having: an elastic core and a thread covering cemented to the core, which comprises winding an initial -thread covering on the core tensioned with coils of the covering spaced from one another, running the core tensioned and initially coveredl as aforesaid through a bath of cementing material capable of being picked up by the initially covered core for cementing the coils of the initial covering to the bodyofthe core, re-

coref'beforefexposure thereof with applied cementi'ngfrmaterial thereon -to the atmospherefand afterward winding a secondary -thread, :covering on the coated core still tensionedfwith coils of the secondary'covering spaced from one'another. i f 'I 8. The method of making elastlc strands having an elastic-core and athread covering 'cemented to the core, which comprises Wind-oy ing an initial thread covering on the core tensionedwith coils ofthev covering spaced from one another', running the core -tensioned and initially covered as aforesaid `through a bath 'of cementing material'capo ablevof being picked up by thelnitially cementing material from the covered core for cementing the coils of the initial covering to the body of the. core, .removing excess cementing `material from the core before exposuregthereof with' applied cementing material thereon to thev atmosphere and afterward winding Ya secondary thread covering o n the coated core still tenspaced from one another after the'exposure of the coated .core to the'atmosphere and be# fore it hascontact with any surface to which the cementin'g Inaterial.ther'eon .may adhere- 'sioned with coils of the'secondary covering 

